This invention relates to the field of interference lithography and more particularly to interference lithography using holey fibers.
The coherent addition of multiple exposure beams produces an interference pattern. An interference lithography system may be used to produce such an interference pattern, but it is often difficult and time consuming to reconfigure, calibrate, and maintain high quality interference patterns through continued use of the system. Radiation losses, component misalignments, and many other factors may contribute to the degradation of quality in the interference pattern.
An interference lithography system and method are provided that substantially eliminate or reduce disadvantages and problems associated with previous systems and methods.
In accordance with one embodiment of the present invention, a method for interference lithography generates an optical signal and communicates the optical signal using a fiber having a cladding region with axially formed holes surrounding a core region. The fiber emits the optical signal to perform interference lithography.
Another embodiment of the present invention is an apparatus for interference lithography that includes a support structure and at least two fibers coupled to the support structure that emit optical signals to perform interference lithography. Each fiber includes a cladding region having axially formed holes surrounding a core region.
Technical advantages of certain embodiments of the present invention include the use of fibers having axially formed holes surrounding a core region to deliver optical signals for interference lithography. These fibers, generally referred to as holey fibers, exhibit single mode characteristics over a much larger range of wavelengths than standard fiber. The single mode core may be smaller than a standard fiber core, which allows light to diverge faster as it exits fiber. This allows the fiber output to be placed closer to a recording plane in an interference lithography device to maintain a flat, central portion of the Gaussian exposure beam intensity distribution across the exposure area. Moreover, these holey fibers improve coupling efficiency, and may be less susceptible to stress and tight bends in the fiber delivery system that, in traditional fibers, may result in a loss of optical energy and changes in the polarization of the optical signal. Furthermore, holey fibers may exhibit significantly higher polarization extinction ratios that allow an optical signal having a linear polarization vector launched into the holey fiber along a polarization axis to maintain its orientation throughout the fiber length. Other advantages will be apparent to one skilled in the art from the following description, figures, and claims.